Random observation: the "Prototype Type-99 EM Radiation Cannon" we see on Yui's screen in this ep is the same thing we see Yui's "uncle" (I get the feeling he's not a blood relation but someone she knows well) showing to that lady from the Five Regent families in ep 1.
Chekhov's Gun much?
Would LOL if Yui pulled it out in ep 5..